Parameter Dependencies

A Simscape™ block parameter is considered visible when it appears in the Simulink Property Inspector, in a block dialog box, or as a block choice on the Simscape context menu. A block parameter is considered configurable or enabled when you can configure it by selecting an option, entering a value, or selecting or clearing a check box. Parameters that are visible but are not enabled are typically dimmed.

The visibility and configurability of some parameters depend on the options that you select for other parameters. Parameter dependencies are typically listed in the parameter description in the documentation for the block. For some blocks, the documentation also includes a parameter dependency table.

Parameter Dependency Tables

Parameter dependency tables show how the visibility and configurability of some parameters depend on the options that you select for other parameters.

Parameter dependency tables indicate which parameter options affect the visibility of other parameters. For example, the next table shows the dependencies for the Effects and Initial Conditions parameters for the Pipe (2P) block from the Simscape > Foundation Library > Two-Phase Fluid > Elements library.

The row numbers in this table are for reference only. The first column of a parameter dependency table typically includes all parameters that are visible by default.

Parameters that affect the visibility or configurability of other parameters are shown in bold text. The options for the parameters that affect other parameters are shown in italic text in the following row of the table. Parameters that do not affect other parameters are shown in plain text.

Effects and Initial Conditions Parameter Dependencies

Row	Parameters and Options
1	Fluid Inertia
2	Off			On
3	Initial fluid regime			Initial fluid regime
4	Subcooled liquid	Two-phase mixture	Superheated vapor	Subcooled liquid	Two-phase mixture	Superheated vapor
5	Initial fluid pressure	Initial fluid pressure	Initial fluid pressure	Initial fluid pressure	Initial fluid pressure	Initial fluid pressure
6	Initial fluid temperature	Initial fluid vapor quality	Initial fluid temperature	Initial fluid temperature	Initial fluid vapor quality	Initial fluid temperature
7				Initial mass flow rate from port A to port B	Initial mass flow rate from port A to port B	Initial mass flow rate from port A to port B
8	Phase change time constant	Phase change time constant	Phase change time constant	Phase change time constant	Phase change time constant	Phase change time constant

The figure shows the Effects and Initial Conditions parameters that are visible by default on the block dialog box for the Pipe (2P) block.

If you change the Fluid Inertia parameter from Off to On, the Initial mass flow rate from port A to port B parameter becomes visible. The table shows this dependency in rows 1, 2, and 7.

If you then change the Initial fluid regime parameter from Subcooled liquid to Two-phase mixture, the Initial fluid temperature parameter is hidden and Initial fluid vapor quality becomes visible. The table shows these dependencies in rows 3, 4, and 6.

Parameter dependency tables also indicate which parameter options enable other parameters. For example, the next table shows the dependencies for the parameters for the Solver Configuration block from the Simscape > Foundation Library > Utilities library. The first column in the table contains row numbers, which are for reference only. The second column includes all parameters that are visible by default.

Parameters that affect the visibility and configurability of other parameters are shown in bold text. The options for the parameters that affect other parameters are shown as selected and cleared check boxes in the following row of the table. Parameters that are shown in plain text are enabled but do not affect other parameters. Parameters that are not enabled are not shown.

Solver Configuration Block Parameter Dependencies

Row	Parameters and Options
1	Start simulation from steady state
2	Consistency tolerance
3	Use local Solver
4
5			Solver type
6			Sample time
7	Use fixed-cost runtime consistency iterations		Use fixed-cost runtime consistency iterations
8
9		Nonlinear iterations	Nonlinear iterations
10		Mode iterations
11	Linear Algebra
12	Equation formulation
13	Delay memory budget [kB]
14	Apply filtering at 1-D/3-D connections when needed
15
16	Filtering time constant

The figure shows the parameters that are visible by default on the block dialog box for the Solver Configuration block. The dimmed parameters, for example, Solver type, are not enabled.

If you select the Use local solver check box, the Use fixed-cost runtime consistency check box becomes selected and these parameters become enabled.

• Solver type

• Nonlinear iterations

• Sample time

Selecting Use local solver does not enable the Mode iterations parameter. The Mode iterations parameter is only enabled when the Use local solver check box is cleared while Use fixed-cost runtime consistency check box is selected.

The table shows these dependencies in rows 3–10.